Square debarking chains? Yes, practical innovation with great results

Function Chains have used their logging experience to produce flail chains and drums that last longer and debark better.

An Australian logging contractor has used his experience of chain flail delimber debarkers to come up with a range of improvements to flail chains and drums. Traditional flail debarkers will have three or four flail drums, with each drum holding six rows of chain, with each row carrying a maximum of 13 chains per row. Conventional 16 mm oval chain links wear at either end due to friction. To obtain longer chain life, each chain can be rotated end for end to the attachment on the drum.

Function chains carried out much research to improve chain life, and finally settled on a square chain link. These links have four angles, which spreads the wear across four corners instead of two. The result is 25 to 58% longer chain life compared to conventional chains. The square flail chain is available in two configurations:
 

• Three oval, five square link flail – This is designed for the oval link to fit into a conventional flail drum, and the five square links being the working links.
• One oval, six square, one oval chain – Designed for maximum life so that the chain can be rotated end for end on the drum.

The curtain chain has also been improved by adding a solid bar welded inside each link. This increases the weight of the chain, preventing bark and branches from passing through, which is especially important when chipping immediately after debarking. The solid bars prevent pieces of wood and branches from being caught in the link, which can open the chain curtain and allow unwanted material to pass through. Function chains also produce an alternative flail drum which has the chain attachments configured to reduce stems passing through that do not make contact with the flails, a common problem with smaller stems. Source: www.functionchains.com.au